It is sometimes necessary to measure components such as rods, pipes and gears. In some instances, these components must be measured to a high degree to accuracy in order to conform to detailed specifications and/or manufacturing tolerances. Typically, these components are measured both during and after the manufacturing process to assure that this accuracy has been achieved.
For example, to determine if a component conforms to particular specifications and/or tolerances, certain dimensions of the component, e.g., the inner and outer diameter, the length, the pitch diameter of gears and/or the distance between selected apertures on the component are measured. To perform these and other measurements, typically a caliper or micrometer is manually supported over the component and adjusted to provide an indication of the selected dimension.
Alternatively, an electronic device can be used to measure the selected dimension of the component, such as shown for example in Gillespie, U.S. Pat. No. 4,567,663. The Gillespie patent shows a wheeled support having a first anvil secured to one end of a track. Components such as sheet stock, templates and panels are supported on parallel support bars on the track and a second anvil is moved along the track into engagement with the selected dimension of a component. A digital display electrically connected to an encoder generates an output indicating the displacement of the second anvil from the first anvil.
Similarly, Caulfield, U.S. Pat. No. 4,700,485, discloses a linear measuring device for measuring a push-pull cable assembly. The Caulfield device comprises a first end block which supports one end of a pair of shafts, and a second end block which supports the other end of the pair of shafts in spaced relation to a support surface. A third block mounted on the shafts is moveable between the first end block and the second end block. The cable assembly is retained between a retaining means mounted in the first end block and a retaining means mounted in the third, moveable block. The third block, having a detector head, is moved along the shafts to put the cable assembly under tension and allow measurement of the length of the cable assembly against a linear scale.
However, these measuring devices are not without drawbacks. For example, manually supporting a caliper or micrometer over a component during the measuring process can result in misreading and error. In particular, operator fatigue, vibration and movement of the component, and inadvertent movement of the caliper or micrometer can lead to incorrect results.
Moreover, Caulfield's measuring device is primarily designed to measure the length of a push-pull cable assembly by putting the cable assembly under outward tension. Caulfield's device is not designed to measure in the inward direction, such as measuring the outside diameter of a component. Moreover, Caulfield does not provide a support surface for measuring the component with the retaining means. The cable assembly is retained between the retaining means and hence is supported by the outward tension applied by the retaining means.
Similarly, the Gillespie measuring device is only adapted to measure the outer dimension of components such as elongated sheet stock, templates and panels. Gillespie's device is not adapted to measure in the outward direction, such as measuring the inside diameter of a component. Moreover, the track of the Gillespie device has a limited surface area for supporting these components during the measuring process. Although a portion of the component can be set on the support bars on the track, the track is relatively thin and is not designed to support a wide variety of components such as rods, pipes and gears. Therefore, it can be necessary to manually support the components across the support bars on the track which, as described above with respect to calipers and micrometers, can lead to incorrect results.